To provide an opening device for fiber bundle which can be stably opened in high efficiency even when fiber bundle to be opened is so called fiber having high elastic modulus or carrying speed in increased and an opening method of fiber bundle utilizing the opening device and a method for producing prepreg by which prepreg obtained by impregnating a resin into opened fiber bundle is nonconventionally upgraded.
This opening device of fiber bundle is constituted of a plurality of rollers for transferring fiber bundle and at least two systems of mechanisms for applying vibration to the fiber bundle by changing axial center position of a vibration applying body for applying vibration to the fiber bundle to be transferred. In the opening device, a frequency f1 applying a first vibration- applying mechanism positioned on upstream side to transferring direction of the fiber bundle to the fiber bundle and a frequency f2 applying a second vibration applying mechanism positioned on downstream side to the fiber bundle each satisfy the formulas 0.5≤f1≤5 Hz and 15≤f2≤30 Hz.
AKASE DAISAKU
MATSUMAE HIDEYO
